1. Field of the Invention
The present invention relates generally to a fin-shaped structure and method thereof, and more specifically to a fin-shaped structure which has a ladder-shaped cross-sectional profile, and a method thereof.
2. Description of the Prior Art
With increasing miniaturization of semiconductor devices, various multi-gate MOSFET devices have been developed. The multi-gate MOSFET is advantageous for the following reasons. Manufacturing processes of multi-gate MOSFET devices can be integrated into traditional logic device processes, and thus are more compatible. In addition, since the three-dimensional structure of the multi-gate MOSFET increases the overlapping area between the gate and the substrate, the channel region is controlled more effectively, which reduces drain-induced barrier lowering (DIBL) effect and short channel effect. Moreover, the channel region is longer for the same gate length, so the current between the source and the drain is increased.
Since transistors in different areas such as logic areas and input/output areas have different purposes, structures of these transistors should be tailored to suit their particular purposes. When forming the structures, electrical demands in each area should be considered.